1. Field of the Invention
The invention generally involves systems for conditioning materials during a drying operation. In particular, it relates to controlling the moisture content of clothes which are being dried in order to eliminate static electricity by preventing overdrying, while allowing adequate drying time for articles which are more difficult to dry.
2. Description of the Prior Art
A typical domestic clothes dryer uses a rotating drum to tumble clothes while exposing them to a heated stream of air. The clothes become dry by losing their moisture to the air stream. It has been difficult to determine the proper length of the drying cycle because of differences in load size and consistency. Employment of dryness sensors has been inadequate in overcoming this problem because of difficulties in sensing dryness accurately and in uniformly drying a non-homogeneous load of clothes.
In the past, the most common approach to overcoming these difficulties has been to time the drying cycle so as to assure dryness of each and every item of clothing in the load. In assuring total dryness, this procedure overdries the clothes and creates the buildup of an electrostatic charge which causes the clothes to cling to each other. There have been proposed solutions to the problem of overdrying based on preconditioning the incoming air prior to its use in the dryer. For example, conditioning the air of a dry cleaning drum in order to prevent excessive drying of goods is taught by the Fuhring U.S. Pat. No. 3,266,166.
However, heretofore known procedures have not been fully adequate in both eliminating the buildup of static electricity in clothes during a drying operation and permitting uniform drying of the clothes.